′�?, with a frequency of 295 cm−1, is attributed into the stretching vibration of Ga–Se bonds. The two-phonon absorption from the 295 cm−1 phonon corresponds into the crystal IR absorption edge, rather than the residual absorption peak. Density functional idea computations clearly show which the residual absorption with the BGSe https://baga4se7-crystal82603.idblogz.com/32985700/baga4se7-crystal-an-overview